Abstract: Compared with traditional steel-concrete composite beam bridges, concrete-filled steel tubular truss girder bridges offer advantages, including light weight, high bearing capacity, superior economic efficiency and short construction period, and are widely used in engineering. Different from solid-web bridges, the deck of concrete-filled steel tubular truss girder bridge operates under point-supported conditions, leading to a pronounced shear lag effect. Therefore, the shear lag effect is studied through theoretical analysis and finite element method in this study. Firstly, based on energy variation principle, the calculation formula of shear lag coefficient is derived. Then, a refined finite element model of concrete-filled steel tubular truss girder bridge is established, and the numerical results are compared with those obtained from the energy variation method, which verifies the accuracy of the proposed theoretical method. The distribution laws of shear lag effect of girder bridges along the transverse bridge direction, longitudinal bridge direction, and deck slab thickness direction are obtained, the influences of load types and load positions are revealed. It is proposed that the effect of shear lag should be considered in the calculation of the deck effective width of concretefilled steel tubular truss girder bridges.